Control device



July 2s, 1942. Y A N MERS 2,291,364

CONTROL DEVICE Filed Hay 29. 1941 H i s Abb 01mm ery Patented July 28,1942 2,291,364 coN'raoL DEVICE l' Alan N. Ayers,

Scotia, N. Y., assigner to' General Electric Company, a corporation ofNew York Application May Z9, 1941, Serial No. 395,741

l2 Claims.

the resumption of normal cycling when the driving motor circuit isopened upon of the defrost temperature.

In carrying out my invention in one form lutilize a temperatureresponsive operating means of the bellows pressure type together with aspring opposing the bellows device, which spring may be adjusted toregulate the operating characteristics of. the control device. Foradjustment of the spring I provide a 'wedge shaped cam member which maybe slidably moved for adjustment of the spring to givea desiredrefrigerator temperaturel or in one position to secure the switchingmeans in an open position thereby to shut down the refrigerator as longas the wedge member remains in that position.

I also provide a second wedge or cam member which is slidable to give asingle predetermined adjustment of the bellows opposing spring so as tocompress the spring and provide for a high defrosting temperature. Ialso provide an extension or arm on the switching means which engagesthe second wedge member when the switching means is moved toits openposition upon the attainment of the high defrost temperature and therebymoves the second wedge member to an ineiective position. The controldevice thereafter operates to maintain the refrigerator the attainmentfor rendering the at the temperature for which the iirst wedge member isadjusted.

For a more complete understanding of my invention, reference should behad to the accompanying drawing, Fig. l of which is a plan view with thetop cover removed of a refrigerator conn trol deviceembodying myinvention; Fig; 2 is a sectional view taken along the line 2-2 of Fig. iwith some 'of the parts not shown; Fig. 3 is an enlarged view lof theoperating and adjustment mechanism of the control device shown in Fig.1; while Figs. 4 and 5 are fragmentary views showing modified forms ofmy invention.

I have shown my invention in one form as applied to a control device forcontrolling a domestic electrically driven refrigerator. It will beunderstood that such devices comprise an electric switch in the circuitof the driving motor for the refrigerator, which switch is actuated bymeans responsive to the temperature in the refrigerator' thereby `tomaintain a predetermined temperature.

I have shown my invention in one form as applied to a refrigeratorcontrol device substantially as described and claimed in United StatesPatent No. 2,050,883, issued on August 11, 1936, to John B. Ford. Thedevice comprises a temperature responsive operating device l0 shown as ametal fluid pressure bellows device which bears on a disk i l made ofinsulating material bearing in turn on a switch operating arm l2 havinga stationary pivot I3. The end of the operating arm l2 is .connectedthrough an over-center spring i4 to operate a flexible switch arm i5having a stationary pivot i6. A movable contact il is carried on theswitch arm, this movable contact cooperating with a stationaryr contacti8.

A helical compression spring I9 bears on the operating arm l2 on theside opposite the bellows i@ and applies a force to the operating arm inopposition to the force .applied by the bellows. My invention relates inparticular to simple and reliable means for adiusting as desired thepressure applied by the spring i9.

An adjustment arm 20 is provided having a stationary pivot 2l, on whicharm bears the end of the spring i9 opposite the end bearing on the armis. For adjustment of the arm, and hence adjustment of the force appliedby the spring is to the arm i2, l'. provide two wedge shaped members 22and 23 which engage the lmovable, end of the adjustment arm 28.Preferably, as shown, the end of the arm it? is provided with a suitablebearing, such as a roller bearing 2d, resting on themembers 122 and 33.Y

The wedge shaped member 22 is utilized to effeet the normal temperatureadjustment of the control device thereby to vary the air temperature inthe refrigerator that is maintained. As shown in the drawing, the member22 is in its extreme ieithand position whereby the arm 20 is lifted, i.e., moved clockwise about its pivot 2i, for maximum compression of thespring i9 and hence maximum operating temperature in the refrigerator.From this point of the upper cam surface or edge 25 of the member 22engaged by the roller bearing 24 the surface 25 is inclined downwardly,as seen in Fig. l of the drawing, so that slidable movement of the wedge22 toward the right hand, as seen in Fig. 1, lowers the left-hand end ofthe arm 20 thereby to decrease the pressure applied by the spring i9.This causes the switch arm i2 to be moved downward. as seen in Fig. l,by a lower uid pressure in the bellows Il) and hence lower temperature1n the refrigerator thereby to reengage the contacts l and i8 and startthe refrigerator motor at a lower temperature. Thus the control deviceis adjusted to maintain a progressively lower temperature in therefrigerator as .the wedge member 22 is moved toward the right hand fromthe position shown in Fig. 1.

Preferably, the lower edge ofv thewedge mem- -ber 22 bears on theadjacent wall oi' the Icasing 22 in which the mechanism is mounted, thefriction between the two parts being sufficient to securethewedgememberinanyadjusted position. For convenience in adjustment aknob 21 is provided on the outside of the ycasing 22, which knob issecured to the wedge member 22 by means of a rigid connection member 22extending through a slot .22' provided for it in the casing. Thus, bypushing the knob 21 laterally along the front of the casing, the wedgemember 22 is adjusted in a direction at right angles to the axis of thepivot 2i thereby to adjust the temperaature being maintained in therefrigerator as desired.

The wedge member 22 is similar in construction to` the wedge manber 22.It is, however, provided with pairs of rollers 22 and 22 (only oneroller of each pair being shown) at opposite ends, which rollers bear onthe inner surface of the casing and provide bearings for reducedfriction between the wedge member and the casing. This' wedge member hasa single operating or effectivee surface 2 I, which surface issubstantially parallel with the inner surface of the casing on whichbear the rollers 22 and 22. Also, the bearing member is provided with arelatively steeply inclined bearing surface 22 arranged toengage theroller .bearing 24 and forming a continuation of the bearing of the camsurface 2|. In a manner similar to the wedge member 22 this wedge memberis slidably movable from the exterior of the casing by means of a knob22.

In the position shown in the drawing the wedge member 22 -is in anineffective position,in which position the roller bearing 24 engages thesteeply inclined wedge surface 22. This surface 22 is so steeplyinclined that an overrunning action is provided. In other words, theroller bearing 24 has suilicient force applied to it by the spring tomove the cam member 22 toward therighthandAsshowninthedrawing, theroller bearing is resting on the wedge member 22. If the wedge member 22is moved toward the right hand, the roller bearing 24 moves downward inengagement with the surface 22. but the engagement of the roller bearingwith the inclined surface 22 of the other wedge member forces the wedgemember 22 -to the right hand out of the way, this wedge member movingfreely l, on its bearings 22 and 22.

For the defrost adjustment, the wedge member 22 is moved toward the lefthand to its extreme positionbymeansoftheknobwhereby the left-hand end ofthe horizontal surface or edge 2ianel'sviththeinnerirurfacevrefrigerator temperature has increased to such a value that the bellowsovercomes the spring I2 and closes the switch contacts to start therefrigerator motor. 'I'his spring setting made by the wedge member 22compresses the' spring sufilciently to produce a temperature higherenough in the evaporator of the refrigerator to effect defrost of theevaporator. When the arml I2 is moved couterclockwise from the positionshown in Fig. l to its closed circuit position, however, the arm 22engages the projection 24 and moves the wedge member 22 toward the righthand far enough to bring the roller bearing 24 onto the surface 22, thusautomatically reestablishing the normal refrigerator operatingcondition.

lhus it will be observed that the defrost setting causes therefrigerator temperature to rise to a predetermined defrost temperatureand when this temperature is reached, the normal operating conditionsare reestablished automatically.

Also, while Fig. l of the drawing shows the wedge member 22 in itsextreme left-hand position for the highest possible refrigeratortemperature, ordinarily during operation of the refrigerator, the wedgemember 22 will be in a po. sition to the right of that shown, giving adesired low refrigerator temperature.

Another feature of the control is an off or continuously switch opensetting which is obtained by moving the wedge member 22 to its extremeright-hand position into engagement with an arm 22 secured to the switcharm I2. More specifically, a laterally extending rprojection 2l on thewedge member 22 engages a laterally extending projection 22 on the lowerend of the arm 22 and moves the contactarm in a coun-- terclockwisedirection about the pivot I2, as seen in Fig. 1, to the open circuitposition. The friction between the .wedge member 22 and the innersurface of the casing 22 is suiiicient to hold the wedge member in thisof! position.

For the purpose of providing limits of move ment of the contact arm twoprojections 22 and 42 are provided on an inner wall of the casingadjacent the lower end of the arm 22, as seen in Fig. 1. TheseIprojections are spaced apart a predetermined distance providing for apredetermined range of angular movement of the switcharm I2asiixedbythemovementofthe end of the arm 22 between the two projections.Theendoftheannisprovidedwithaprojection 4I for the purpose of definingand limiting this movement. i

Also, the projection 22 acts as a stop for the operating arm I2 in itsclosed circuit position.

anarm42ontheswitcharmenglilin8theupper end of this projectiomas seen inPig. 1, wheny theswitcharmiamovedtoitsclosedcircuitposition.

Preferably, the casing 22 for mounting and enclosing the various partaismade of a suitable moulded electrically insulating material such as aphenolic condensation product. 'lhe bellows I2 isinserted fromtheexteriorofthecasingthrough a hole (not shown) provided for thebellows. It issecuredinplacebysecuringaiiangetowhichthebellowaissecuredtoanouterwall ofthecasingbymeanaofboltauand".

Asshowmthestationarycontact I2 issecured to an electrically conductingstrip 42 and ia electricallyconneetedtoanelectricterminalmember 41ontheexteriorofthecasingbymeanaofa screw or rivet 42 which also holdsthese parts armremainsinits opencircuitpositionuntilthe 'lasecuredtothecasing. Asimilarterminaimem.

A ber (not shown) is provided for the movable contact I1, this terminalmember being electrically connected by means of a conducting strip I9and a flexible conducting lead 5I! to the switch arm I5.

It will be understood that the snapping mechanism for 4the switch armconsists of a U-shaped link 5I having -its ends pivoted on a pair ofprojections 52 and,V 53 on the end of the switch arm I2. The over-centersnapping spring I4 has one end connected to the closed end of the link5i and its other end connected to an arm 55 secured to the switch armI5. Suitable electrically insulating stops 56 and 51 are provided forlimiting the movement ofthe link 5I in each of itsv extreme positions.Thus, movement of the operating arm I2 to bring the pivot axis of thelink 5I to one side or the other of the point of connection 58 of thespring with the arm 55 causes the linkv5l to snap from one position toanother and therebysnap the switch arm I5 between its open and closedcircuit positions.

In the modified form shown in Fig. 4 the arm 29 is provided with asecond roller bearing 59 intermediate its length. The defrosting cam 60corresponding to the cam 23 of Figs. 1 to 3 cooperates with this bearing59. The other cam 22 cooperates as before with the roller bearing N.This arrangement has the advantage oi separating the two operating camsfrom each other whereby the cam 60 may be shortened if desired.

In the arrangement of Fig. 5 I have provided a single adjustment cam,only this cam being provided with the combined adjustment cam surfacesof the two .cams shown in Figs. l t 3. In

Fig. 'the single cam BI has an adjustment sur- Aface 62 forgiving thenormal box ,temperature adjustment to the armZIl. This surface 62corresponds with the surface 25 oi the cam 22. In addition, the cam 6Ihas a flat or level surface t3 raised above the surface 62, whichsurface 63 gives the defrost adjustment. Also, the cam 6l is providedwith a projection which is engaged by an arm or projection carried bythe operating arm I2 and corresponding with the arm 35 oi Figs. 1 to 3'whereby the'cam 6I is automatically moved from the defrost setting onthe surface E3 to the normal adjustmentv surface 62 after theycompletion of a single high temperature defrost cycle. I

The arrangements of Fig. 5, while having the advantage of simplicityover the double cam arrangementshas the disadvantage that after the derost cycle the control device is adjusted to m tain a predetermined hightemperature corresponding to theA position to which the cam 6I isreturned after the defrost cycle. Ordinarily the cam 5I will be movedtoward the right hand after the completion of the defrost cycle farenough to permit the roller bearing 24 to engage the surface 62, butprobably the roller bearing will be located at the right-hand end of thesurface 62. Therefore, if 'a lower temperature is desired in therefrigerator, the cam 6I must be adjusted manually toward the right handto some such position as indicated in'Fig. 5.

While I have shown a particular embodiment of my invention, it will beunderstood, of course, that I do not wish to be limited thereto, sincemany modifications may be made and I, therefore, contemplate by theappended claims to cover any such modifications as fall within the truespirit and scope of my invention.

What Iclaim as new and desire to secure by Letters Patent of the UnitedStates is:

1. A control device comprising an operating member, a temperatureresponsive device for actuating said member, a spring for applying aforce in* opposition to said temperature responsive device, cam meansmounted for slidable movement from a first position to a second positionto vary the force applied by said spring, and means actuated by saidoperating member for engaging and moving said cam .means with saidoperating member when said operating member is moved by said temperatureresponsive device in response to a predetermined temperature thereby toreturn said cam means to said first position.

2. A control device comprising an operating member, a temperatureresponsive device for actuating said member, a spring for applying aforce in opposition to said temperature responsive device, an adjustmentmember for said spring provided with bearing means, cam means engagingsaid bearing means mounted for slidable movement from a first positionto a second position to vary the compression of said spring forpredetermined temperature settings, and means actuated by said operatingmember for engaging and moving said cam means with said operating memberwhen said operating member is moved by said temperature responsivedevice in response to a predetermined temperature thereby to return saidcam means to said iirst position.

3. A control device comprising a switch operating'member, a temperatureresponsive device for operating said member, a spring for applying aforce in opposition to said temperature responsive device, an adjustmentmember for said spring provided with bearing means, cam means providedwith a plurality of cam faces mounted for slidable movement selectivelyinto engagement with said bearing means thereby to compress said springfor predetermined temperature settings, and means actuated by saidoperating member for engaging said cam means when said operating memberis moved by said temperature responsive device in response to apredetermined temperature thereby to move one of said cam faces to anineiective position.

4. A control device comprising a switch operating member, a temperatureresponsive device for operating said member, a spring for applying aforce inopposition to said temperature responsive device, an adjustmentmember for said spring provided with bearing means, cam means engagingsaid bearing means for securing said adjustment member in one of aplurality of different temperature positions, meansA for adjusting saidcam means between predetermined positional limits thereby to vary theposition of said adjustment member between predetermined temperaturelimits, and an arm on said operating member'for engaging said cam meansthereby' sive device, an adjustment member for said spring` providedwith bearing means, cam means engaging said bearing means for securingsaid adjustment member in one of a plurality of different temperaturepositions, means ior adjusting said cam means thereby to vary theposition of said adjustment member for a desired temperature position,and means actuated by said operating member for moving said cam means toa lower temperature positionwhen said operating member is moved by saidtemperature responsive device in response to a predetermined hightemperature for which said cam means was adjusted.

6. A refrigerator control device comprising a switch operating member, atemperature responsive device for operating said member, a spring forapplying a force in opposition to said temperature responsive device, anadjustment member for said spring provided with a bearing, a cam membermounted for slidabie movement from an ineffective position intoengagement with said bearing thereby to compress said spring for apredetermined temperature setting, an arm on said switch member forengaging said cam when said operating member is moved by saidtemperature responsive device in response to said predeterminedtemperature thereby to move said cam to an ineifective position, and asecond cam member engaging said bearing to maintain differenttemperature setting when said first cam is in said ineffective position.

'7. A refrigerator control device comprising switching means, a pressuretemperature responsive device for operating said switching means, an armhaving a fixed pivot, an adjusting spring mounted between the end ofsaid arm and said pressure device so as to oppose the movement of saidpressure device in response to an increase in temperature, a bearing onthe end of said arm. a wedge shaped adjustment member normally engagingsaid bearing so as to hold said arm in a predetermined position. saidwedge shaped member being movable to,vary the position of the end ofsaid arm and thereby adjust the temperature at which said switchingmeans is operated, and a projection on said wedge member for securingsaid switching means in its open position when said wedge member hasbeen moved to its lowest temperature position.

8. A refrigerator control device comprising switching means, a pressuretemperature responsive device for operating said switching means, an armhaving a fixed pivot, an adjusting spring mounted between the end ofsaid arm and said pressure device so as to oppose the movement of saidpressure device in response to an increase in temperature, a bearing onthe end of said arm, a wedge shaped member cooperating with said bearingmovable to move said arm to a predetermined position thereby to adjustsaid spring for a predetermined defrost temperature, and an operatingarm on said switching means arranged to engage said wedge member andreturn said wedge member to an ineffective position when said switchingmeans is moved to a closed position by said pressure means in responseto said predetermined defrost temperature.

9. A refrigerator control device comprising switching means, a pressuretemperature responsive device for operating said switching means, aspring adjustment member, an adjusting spring mounted between saidmember and said'pressure device so as to oppose the movement ofl saidpressure device in response to an increase in temperature, bearing meanson said member, a wedge shaped adjustment memberlnormallyenga'ingsaidbearingmeanssoasto hold said member in apredetermined position,

the position of said member and thereby adjust the pressure applied bysaid spring and the temperature at which said switching `means isoperated, a projection on said wedge member for securing said switchingmeans in its open position when said wedge member is moved to an extremetemperature. position, a second wedge shaped member cooperating withsaid bearing means movable to move said arm to a predetermined positionthereby to adjust said spring for a predetermined extreme temperature,and an operating projection on said switching means cooperating withsaid second wedge member so as to return said second wedge member to anineffective position when said switching means is moved to one positionby said pressure device in response to said predetermined extremetemperature.

10. A refrigerator control device comprising switching means, a pressuretemperature responsive device for operating said switching means. an armhaving a fixed pivot, an adjusting spring mounted between the end ofsaid arm and said pressure device so as to oppose thermovement of saidpressure device in response to an increase in temperature, a bearing onthe end of said arm, a wedge shaped adjustment member normally engagingsaid bearing so as to hold said arm in a predetermined position, saidwedge shaped member being movable to vary the position of the end ofsaid arm and thereby adjust the pressure applied by said spring and thetemperature at which said switching means is operated. a projection onsaid wedge member for securing said switching means in its open positionwhen said wedge member is moved to its lowest temperature position, asecond wedge shaped member cooperating with said roller bearing movableto move said arm to a predetermined position thereby to adjust saidspring for a predetermined defrost temperature. and an operating arm onsaid switching means arranged to engage said second wedge member andreturn said second wedge member to an ineifective position when saidswitching means is moved to a closed position by said pressure device inresponse to said predetermined defrost temperature.

ll. A control device comprising an operating member, a temperatureresponsive device for actuating said operating member, a spring bearingon said operating member and applying a force continuously to saidoperating member in opposition to said temperature responsive device. asecond member movable from a nrst position to a second position to varythe force applied by said spring to said operating member, and aprojection on said operating member for engaging said second member whensaid operating member is moved by said temperature responsive device tocompress said spring thereby to return said second member to said tlrstposition.

12. A control device comprising an operating member. a temperatureresponsive device for actuating said member, a spring bearing on saidmember and applying a force continuously to said member in opposition tosaid temperature responsive device, a cam movable from a first positionto a second position to compress said spring and thereby increase theforce applied by said spring to said operating member, and an operatingpropection on said operating member in position to engage said cam uponcompression of said spring by said temperature responsive device therebytoreturnsaidcamtosaidfirstposition said wedgeshaped member being movableto vary ALAN N. AYERS.

